Fig. 1

Fibre type distribution (a, c) and cross-sectional area (CSA) (b, d) of the fibre types in the high oxidative (a, b) and low oxidative (b, d) parts of the gastrocnemius medialis muscle. Fibre type composition (left) and CSA of the different fibre types (right). There were no significant changes in fibre type composition during ageing or alfacalcidol treatment. The CSA of the type IIa fibres in the high oxidative part of the old vehicle group were larger than that of the adult group. In the low oxidative part, type IIb fibres of the alfacalcidol-treated animals were significantly smaller compared to the age-matched vehicle group. CA control adult, A6WO (alfacalcidol for 6 weeks, old), old rats treated with alfacalcidol for 6 weeks, V6WO (vehicle for 6 weeks, old), old rats treated with vehicle for 6 weeks; ^#different from CA (P = 0.018); *different from V6WO (P = 0.029); (repeated-measures ANOVA, Bonferroni posthoc); data are represented as mean ± SEM